U.S. Pat. No. 6,837,016 describes an extremely successful and important full-moment, collar-form, nodal connection between a column and a beam in the frame of a steel frame building structure. This nodal connection, now in use in a number of building structures in various locations particularly where high seismic activity is experienced, offers a number of very important advantages over prior art column/beam nodal connections. The connection is one which may readily be prepared in an off-building-site manner within the realm of a factory for precision computer control and accuracy, and additionally, one which has a number of important field-assembly speed and safety advantages not present in or offered by prior art nodal connection arrangements. For example, no non-disconnectable welding needs to take place irreversibly locking a column and a beam, and beams may be lowered by gravity quickly into place to become immediately, by gravity lowering alone, seated in proper spatial orientation relative to the columns with they are associated, and with the result that a full seismic-capable moment connection exists at the very moment that gravity seating and locking take place during a beam-lowering operation.
While this prior-developed nodal connection structure has met with a great deal of acclaim and success, I have recognized that there is room for improvement in certain respects, and the nodal connection proposed by the present invention specifically addresses that improvement-need recognition.
Among the advances offered by the present invention are an improvement in the way that a resulting nodal connection handles certain kinds of loads, such as prying loads, and additionally that the new connection's modified components possess a certain quality of structural universality which enables the manufacture of just a few different components to offer the possibility for applying these components easily to building-frame beams having different web depths within a range of conventional beam-web depths.
As those skilled in the art will recognize on viewing the drawing figures in this case, and on reading the detailed description of the invention which is presented below, the structure presented by this invention offers a number of other interesting and important features and advantages which are relevant to the fabrication and performance of a multi-story steel building frame.
Accordingly, proposed by the present invention is a unique, collar-form, full-moment nodal connection which is referred to herein as a halo/spider connection. This “halo/spider” reference addresses certain visual qualities of the proposed connection which include the fact that, in its collar-form arrangement, (a) it includes an outer collar to which the ends of beams may be attached, which collar appears to float as a circumsurrounding, and somewhat spaced, halo around the perimeter of the cross-section of an associated beam, and (b) that this halo collar is anchored through gravity-lock seating to the outside of a column via outwardly extending standoffs (like legs) which extend from the corners of a column in a fashion which suggests, as this arrangement is viewed along the axis of a column, the anatomy of a spider body with short legs.
With respect to the opportunity provided by the structure of the present invention to handle different beam depths, the design of the structure of this invention is such that there are simply two, different, specific components/elements that are employed in the halo/spider organization which need only to be cross-divided, separated, and then reunited in a spaced-apart condition through “extender structure” in order to permit employment of all the nodal connection components successfully with beams having different depths lying within the conventionally (today) recognized range of beam depths that define steel building frame structures employed in different settings and for buildings of different sizes and designs.
These and other features and advantages which are offered by the invention will become more fully apparent as the description thereof which follows in detail below is now read in conjunction with the accompanying drawings.